共查询到20条相似文献，搜索用时 31 毫秒
1.
In the Tarim Basin, dolomite, which formed during the middle Cambrian associated with evaporites, has been attributed to the sabkha-style dolomite formed during the syndepositional period. The sedimentary microfacies suggests dolomite formation in the middle Cambrian is an ancient analogue of the sabkha of Abu Dhabi. Poorly crystallised dolomite spheroids or ovoids within or on the surface of dolomite crystals are a common phenomenon that can be widely observed in different stromatolites in the upper part of the intertidal zone and strongly resemble the morphology in modern sabkha dolomite-producing microbial mats and in microbial culture experiments. These lines of evidence suggest organic substrates for dolomite nucleation. Dolomite formation in the middle Cambrian in the Tarim Basin has been considered a classic analogue for carbonate and evaporate assemblages. The extent of microbial dolomite in ancient sabkha environments is proposed as an alternative model for dolomite formation, in which the mineral properties of organic substrates play a crucial role. 相似文献
2.
SUMMARY
Study of 176 ft. (53.7 m) of core from the Arab/Darb Formation of the Umm Shaif Field, Abu Dhabi Marine Areas, has revealed a sequence of sediments which can be related to nine distinct cycles of sabkha formation. The sabkha cycle consists of a basal algal grainstone/boundstone (which is interpreted as a shoal) passing upwards through lagoonal dolomite, intertidal algal mat and into a final supratidal development of nodular anhydrite and associated dolomite. Dolomiti-sation and the formation of nodular anhydrite were early-stage products of diagenesis. Poikilotopic anhydrite is common in the lagoonal dolomites but it is thought that this was not formed until the sediment was completely lithified.
Stylolites, although of small amplitude, are more common in dolomite than in limestone; a generalisation which is at variance with earlier observations. 相似文献
Study of 176 ft. (53.7 m) of core from the Arab/Darb Formation of the Umm Shaif Field, Abu Dhabi Marine Areas, has revealed a sequence of sediments which can be related to nine distinct cycles of sabkha formation. The sabkha cycle consists of a basal algal grainstone/boundstone (which is interpreted as a shoal) passing upwards through lagoonal dolomite, intertidal algal mat and into a final supratidal development of nodular anhydrite and associated dolomite. Dolomiti-sation and the formation of nodular anhydrite were early-stage products of diagenesis. Poikilotopic anhydrite is common in the lagoonal dolomites but it is thought that this was not formed until the sediment was completely lithified.
Stylolites, although of small amplitude, are more common in dolomite than in limestone; a generalisation which is at variance with earlier observations. 相似文献
3.
4.
Diagenetically altered Pleistocene dolomite occurs in the shallow subsurface of the Arabian Gulf, offshore of Al Jubayl, Saudi Arabia. This dolomite accumulated in relatively shallow marine to sabkha depositional environments. In contrast with the thin extent of most other Quaternary sabkha and sabkha-related dolomite deposits, these deposits comprise a thick (>56 m) accumulation. Additionally, this Pleistocene dolomite displays a high degree of ordering and has a more nearly ideal stoichiometric composition than the dolomite from the depositionally and diagenetically analogous Abu Dhabi sabkha complex. The Pleistocene dolomite also has lower δ13 and δ18O values than the modern Abu Dhabi sabkha dolomite, and higher values than those commonly reported for analogous dolomite from the ancient rock record. The low δ18O values, in conjunction with the geological setting, indicate that the diagenetic waters were meteoric or mixed meteoric and marine in composition. Thus, the degree of ordering, stoichiometric and stable isotopic values indicate that this dolomite has undergone diagenetic alteration relative to its presumed Holocene precursor. 相似文献
5.
In the modern hypersaline carbonate lagoon and sabkha sedimentary environments of Abu Dhabi (United Arab Emirates), three types of organic matter originate respectively from microbial mat, Avicennia mangrove, and Halodule lagoonal seagrass. The study of recent sedimentary processes and cross sections through the sabkha sediments lead to the definition of organo-sedimentary facies based on geochemical and sedimentological criteria. This permits the construction of an organo-sedimentary sequence which expresses the Holocene sedimentary record involving a transgressive and a regressive sequence. The various organic facies occur in both sequences.Heterogeneity within the individual organic facies reflects several factors, including sedimentation dynamics, mineral matrix, oxidation and reduction, and selective organic and mineral diagenesis. These parameters are discussed in terms of depositional environment and location within the organo-sedimentary sequence. Changes in distribution, quantity, and preservation potential of the buried organic matter are discussed in terms of sea level changes and sedimentary accretion rates. 相似文献
6.
A quantitative approach to sedimentary surface structures contoured by the interplay of microbial colonization and physical dynamics 总被引：4，自引：0，他引：4
In the tidal flats of Mellum Island (southern North Sea), biofilms and microbial mats, generated largely by cyanobacteria, colonize the sedimentary surfaces. Biostabilization effects and biomass enrichment influence erosional and depositional dynamics resulting from tidal flushing and storm surges. The overlapping of both biological and physical forces causes the development of characteristic sedimentary structures. To obtain a quantitative expression of the degree of effectiveness of microbial colonization in the formation of structures in an extended tidal area, a modification index (MOD-I) was developed based on the following values: (i) the proportion of mat-covered area related to a defined investigation area (IA ); (ii) the degree of steepness of slope angles of raised erosional remnants (IS ); and (iii) the degree of microbial levelling of a rippled sedimentary surface (IN ). The MOD-I was calculated for several defined regions within the study area, and both winter and summer situations were considered. The MOD-I values show, first, that the lower intertidal zone is characterized by index values approaching zero. This implies that microbially induced effects in this zone are negligible, even in summer. Second, the upper intertidal zone is characterized by lower index values in winter and relatively high values in summer. This implies a predominantly seasonal control on the biofilm development in this zone. Third, in the lower supratidal zone, the index values are almost identical during both winter and summer. This implies non-seasonal biological effects in this zone. Concomitant empirical studies on the composition of microbial mats and films suggest that the dominant microbial type influences the MOD-I value. 相似文献
7.
陆表海台地沉积充填模式及内克拉通碳酸盐岩勘探新启示 总被引：1，自引：0，他引：1
内克拉通陆表海盆地是古老碳酸盐建造形成的重要场所。除其顶部风化壳岩溶储层外,广泛分布的内幕非岩溶改造的白云岩勘探长期未受到足够的重视。近年来,随着深层、超深层勘探技术的进步,内幕陆表海白云岩陆续获得油气勘探新发现,但其预测难度远比镶边台地中的礁滩"移动靶"更大。为更好地揭示这类未经岩溶改造的白云岩储层的宏观发育分布规律,本文研究了鄂尔多斯盆地奥陶系马家沟期和四川盆地雷口坡期陆表海台地的高精度岩相古地理和沉积充填模式。结果表明:陆表海台地一般形成于温室期低纬度干燥气候下的稳定内克拉通盆地,与盐湖伴生的台地潮坪广泛分布是其标志性的沉积特征,微环境可进一步划分为潮上带泥云坪、上潮间带云坪、上潮间带微生物席、下潮间带席状潮缘滩、上潮下带灰云质澙湖、下潮下带膏云质澙湖;虽然内克拉通陆表海台地是一个相对静态的沉积环境,其沉积建造并非平板一块,海平面的升降变化往往会在相对平坦的陆表海内引起大幅度的相带迁移,造成潮上带、潮间带、潮下带频繁交互;相带频繁往复迁移过程中,潮间带的晶粒/颗粒/微生物白云岩受到盐湖、古隆起或潮坪岛的制约,形成大面积分布的席状富孔白云岩透镜体;陆表海沉积层序结构为典型的向上变浅序列,主要发育潮坪进积楔和潮坪岛拼嵌两种沉积充填模式,这两种模式形成的席状白云岩透镜体在层序结构和厚度都能很好地对比,通常延伸都在100km以上,甚至可跨越整个陆表海台地,是一个能够媲美台缘礁滩相的油气勘探新领域。 相似文献
8.
Yuzhu Ge Chelsea L. Pederson Stephen W. Lokier Jan P. Traas Gernot Nehrke Rolf D. Neuser Katja E. Goetschl Adrian Immenhauser 《Sedimentology》2020,67(5):2426-2454
Modern cemented intervals (beachrock, firmgrounds to hardgrounds and concretionary layers) form in the lagoon and intertidal sabkha of Abu Dhabi. Seafloor lithification actively occurs in open, current-swept channels in low-lying areas between ooid shoals, in the intertidal zone of the middle lagoon, some centimetres beneath the inner lagoonal seafloor (i.e. within the sediment column) and at the sediment surface the intertidal sabkha. The concept of ‘concretionary sub-hardgrounds’, i.e. laminar cementation of sediments formed within the sediment column beneath the shallow redox boundary, is introduced and discussed. Based on calibrated radiocarbon ages, seafloor lithification commenced during the Middle to Late Holocene (ca 9000 cal yr bp ), and proceeds to the present-day. Lithification occurs in the context of the actualistic relative sea-level rise shifting the coastline landward across the extremely low-angle carbonate ramp. The cemented intervals are interpreted as parasequence boundaries in the sense of ‘marine flooding surfaces’, but in most cases the sedimentary cover overlying the transgressive surface has not yet been deposited. Aragonite, (micritic) calcite and, less commonly, gypsum cements lithify the firmground/hardground intervals. Cements are described and placed into context with their depositional and marine diagenetic environments and characterized by means of scanning electron microscope petrography, cathodoluminescence microscopy and Raman spectroscopy. The morphology of aragonitic cements changes from needle-shaped forms in lithified decapod burrows of the outer lagoon ooidal shoals to complex columnar, lath and platy crystals in the inner lagoon. Precipitation experiments provide first tentative evidence for the parameters that induce changes in aragonite cement morphology. Data shown here shed light on ancient, formerly aragonite-cemented seafloors, now altered to diagenetic calcites, but also document the complexity of highly dynamic near coastal depositional environments. 相似文献
9.
Tentative kinetic model for dolomite precipitation rate and its application to dolomite distribution
The ‘dolomite problem’ has a long history and remains one of the most intensely studied and debated topics in geology. Major amounts of dolomite are not directly forming today from seawater. This observation has led many investigators to develop geochemical/hydrologic models for dolomite formation in diagenetic environments. A fundamental limitation of the current models for the growth of sedimentary dolomite is the dearth of kinetic information for this phase, in contrast to that available for calcite and aragonite. We present a simple kinetic model describing dolomite growth as a function of supersaturation using data from published high temperature synthesis experiments and our own experimental results. This model is similar in form to empirical models used to describe precipitation and dissolution rates of other carbonate minerals. Despite the considerable uncertainties and assumptions implicit in this approach, the model satisfies a basic expectation of classical precipitation theory, i.e., that the distance from equilibrium is a basic driving force for reaction rate. The calculated reaction order is high (~ 3), and the combined effect of high order and large activation energy produces a very strong dependence of the rate on temperature and the degree of supersaturation of aqueous solutions with respect to this phase. Using the calculated parameters, we applied the model to well-documented case studies of sabkha dolomite at Abu Dhabi (Persian Gulf), and organogenic dolomite from the Gulf of California. Growth rates calculated from the model agree with independent estimates of the age of these dolomites to well within an order of magnitude. A comparison of precipitation rates in seawater also shows the rate of dolomite precipitation to converge strongly with that of calcite with increasing temperature. If correct, this result implies that dolomite may respond to relatively modest warming of surface environments by substantial increases in accumulation rate, and suggests that the distribution of sedimentary dolomite in the rock record may be to some extent a temperature signal. 相似文献
10.
Characterization of the Microbial Dolomite of the Upper Sinian Dengying Formation in the Hanyuan Area of Sichuan Province, China 总被引：1，自引：1，他引：0
The algal dolostone of the Upper Sinian Dengying Formation (corresponding to the Ediacaran system) in the Upper Yangtze Platform of China possesses a rich diversity of microorganisms and is an ideal site for the study of ancient microbial dolomite. We focused on algal dolostone and its microbial dolomite in the Hanyuan area of Sichuan Province, China. The macroscopic petrological features, microscopic morphology, texture characteristics of the fossil microorganisms and microbial dolomite, and geochemical characteristics were investigated. We found rich fossil microorganisms and microbial dolomites in the laminated, stromatolithic, uniform and clotted (algal) dolostones. The microorganisms present were mainly body fossils of cyanobacteria (including Renalcis, Girvanella, Nanococcus, and Epiphyton) and their trace fossils (including microbial mats (biofilms), algal traces, and spots). In addition, there was evidence of sulfate-reducing bacteria (SRB), moderately halophilic aerobic bacteria, and red algae. The microbial dolomites presented cryptocrystalline textures under polarizing microscope and nanometer-sized granular (including spherulitic and pene-cubical granular) and (sub) micron-sized sheet-like, irregular, spherical and ovoidal morphologies under scanning electron microscope (SEM). The microbial dolomites were formed by microbially induced mineralization in the intertidal zone and lagoon environments during the depositional and syngenetic stages and microbially influenced mineralization in the supratidal zone environment during the penecontemporaneous stage. The microbial metabolic activities and extracellular polymeric substances (EPS) determined the morphology and element composition of microbial dolomite. During the depositional and syngenetic stages, the metabolic activities of cyanobacteria and SRB were active and EPS, biofilms and microbial mats were well-developed. EPS provided a large number of nucleation sites. Accordingly, many nanometer-sized pene-cubical granular and (sub) micron-sized sheet-like microbial dolomites were formed. During the penecontemporaneous stage, SBR, cyanobacteria, and moderately halophilic aerobic bacteria were inactive. Furthermore, nucleation sites reduced significantly and were derived from both the EPS of surviving microorganisms and un-hydrolyzed EPS from dead microorganisms. Consequently the microbial dolomites present nanometer-sized spherulitic and micron-sized irregular, spherical, and ovoidal morphologies. Overall, the microbial dolomites evolved from nanometer-sized granular (including spherulitic and pene-cubical granular) dolomites to (sub) micron-sized sheet-like, irregular, spherical and ovoidal dolomites, and then to macroscopic laminated, stromatolithic, uniform, and clotted dolostones. These findings reveal the correlation between morphological evolution of microbial dolomite and microbial activities showing the complexity and diversity of mineral (dolomite)-microbe interactions, and providing new insight into microbial biomineralization and microbial dolomite in the Precambrian era. 相似文献
11.
An association of structures is documented from a Lower Proterozoic carbonate sequence in South Africa: this is dominated by finely laminated material which may display flat (smooth), small domical (blister), crinkled (tufted) and pustular (mamillate) surface. The lamination may display overfolded structures and contain flat encapsulated features. Lens-like flat-pebble breccias are common, while edgewise breccias were seen less frequently. Small-scale features suggestive of vertical algal moulds were also recorded. This facies is considered to be analogous to contemporary tidal flat sedimentation developed in specific settings at Shark Bay in Western Australia, and at Abu Dhabi where it is the dominant growth form. This analogy is most notably clear in relation to the protected embayments at Shark Bay, and as a result, an inner intertidal to marginal supratidal environment is suggested for the specific horizons under consideration from the Transvaal Dolomite. Other structures are associated with this facies. These include larger domes, coarser bedding, oolites, ripple-marks and, in one case, columnar stromatolites. Using the basic facies as an environmental datum, a model is developed in which these latter structures extend into the outer intertidal zone. They are also considered to be associated with varying states of turbulence in the intertidal regime. 相似文献
12.
微生物活动导致铁氧化被认为是前寒武纪铁建造和红层形成的重要机制之一,但是地质记录中却鲜有相关证据。针对这一问题,本研究选择华北古元古代末的大红峪组微生物席成因构造(MISS)为研究对象,通过沉积学和矿物学的综合研究,揭示微生物活动在前寒武纪铁循环中的关键作用。研究表明:华北井陉大红峪组发育大量以砂裂为代表的MISS,指示当时潮间带至潮上带广泛发育微生物席;非微生物席层发育大量原位和近距离搬运的海绿石,指示低氧富铁的浅海和孔隙水化学条件,而相邻微生物席层则发生了显著的赤铁矿化,指示相对更氧化的沉积环境。考虑到微生物席层与相邻(厘米级)非微生物席层间微生物活动与矿物组成的明显差异,笔者提出微生物活动可能是导致当时低氧铁化浅海环境局部铁氧化的重要机制。本研究提供了微生物参与Fe2+离子氧化的重要证据,对揭示前寒武纪红层和大规模铁建造形成机制具有启示意义。 相似文献
13.
J.R. Stewart S. Aspinall M. Beech P. Fenberg P. Hellyer N. Larkin S.W. Lokier F.G. Marx M. Meyer R. Miller P.S. Rainbow J.D. Taylor J.E. Whittaker K. Al-Mehsin C.J. Strohmenger 《Quaternary Science Reviews》2011,30(25-26):3675-3690
Whale remains (a left and right mandible, scapula, humerus and fragmentary radius and ulna as well as parts of the cranium and rostrum) belonging to a probable humpback whale (Megaptera cf. novaeangliae) were found in the well-described sabkha sequence exposed in the Musaffah Industrial Channel, Abu Dhabi, United Arab Emirates. More precisely, the whale remains were found in a series of sediments representing a range of lagoonal facies. The sediments surrounding the whale bones were age-dated at approximately 5200 14C yrs BP and are therefore interpreted to correspond to the previously documented late Flandrian sea-level peak, preceding a fall in sea-level which culminated in the supratidal sabkha overprint of the carbonates. Associated with the whale remains is an assemblage of molluscs, foraminifera and ostracods. Together with the inferred presence of sea grass and algae, these facies are interpreted to indicate a very shallow subtidal to intertidal lagoonal environment. Cirripede remains found associated with the skeleton were identified as those of the whale barnacle Coronula diadema and hence had their origins with the whale. Significantly, the low species diversity of microfossils suggests that higher salinities existed in the mid-Holocene lagoon than are present in modern counterparts. This is here inferred to be related to the onset of continental aridity in Arabia during the mid-Holocene. 相似文献
14.
Tentative kinetic model for dolomite precipitation rate and its application to dolomite distribution
The dolomite problem has a long history and remains one of the most intensely studied and debated topics in geology. Major amounts of dolomite are not directly forming today from seawater. This observation has led many investigators to develop geochemical/hydrologic models for dolomite formation in diagenetic environments. A fundamental limitation of the current models for the growth of sedimentary dolomite is the dearth of kinetic information for this phase, in contrast to that available for calcite and aragonite.We present a simple kinetic model describing dolomite growth as a function of supersaturation using data from published high temperature synthesis experiments and our own experimental results. This model is similar in form to empirical models used to describe precipitation and dissolution rates of other carbonate minerals. Despite the considerable uncertainties and assumptions implicit in this approach, the model satisfies a basic expectation of classical precipitation theory, i.e., that the distance from equilibrium is a basic driving force for reaction rate. The calculated reaction order is high (~ 3), and the combined effect of high order and large activation energy produces a very strong dependence of the rate on temperature and the degree of supersaturation of aqueous solutions with respect to this phase.Using the calculated parameters, we applied the model to well-documented case studies of sabkha dolomite at Abu Dhabi (Persian Gulf), and organogenic dolomite from the Gulf of California. Growth rates calculated from the model agree with independent estimates of the age of these dolomites to well within an order of magnitude. A comparison of precipitation rates in seawater also shows the rate of dolomite precipitation to converge strongly with that of calcite with increasing temperature. If correct, this result implies that dolomite may respond to relatively modest warming of surface environments by substantial increases in accumulation rate, and suggests that the distribution of sedimentary dolomite in the rock record may be to some extent a temperature signal. 相似文献
15.
周得科 《沉积与特提斯地质》1991,11(1):1-7
鄂东地区早三叠世中晚期为潮间带上部、潮上带以及萨布哈沉积环境。以前有人认为:(1)燕山期岩浆岩是控制大冶式铁铜(金银钴硫)矿床生成的内因,围岩条件是控制矿床生成的外因;(2)不同时代的地层控制着不同种类矿化的丰度,围岩性质的差异制约着矿化的强度。统计表明,80％以上的铁、铜、钼矿储量与潮间带上部、潮上带及萨布哈相的大冶群第四至第七段(T_1dy~(4-7)碳酸盐岩关系密切;黄石—广济(今武穴市)一带的铅锌矿与泻湖相的第三至第五段(T_1dy~(3-5)碳酸盐岩关系密切。 相似文献
16.
B. CHARLOTTE SCHREIBER GERALD M. FRIEDMAN† ARVEDO DECIMA‡ EDWARD SCHREIBER 《Sedimentology》1976,23(6):729-760
In Sicily, Messinian evaporitic sedimentary deposits are developed under a wide variety of hypersaline conditions and in environments ranging from continental margin (subaerial), to basin-margin supratidal, to intertidal, to subtidal and out into the hypersaline basin proper. The actual water depth at the time of deposition is indeterminate; however, relative terms such as ‘wave base’ and ‘photic zone’ are utilized. The inter-fingering relationships of specific evaporitic facies having clear and recognizable physical characteristics are presented. These include sub-aerial deposits of nodular calcium sulphate formed displacively within clastic sediments; gypsiferous rudites, arenites and arenitic marls, all of which are reworked sediments and are mixed in varying degrees with other clastic materials (subaerial, supratidal, and intertidal to deep basinal deposits). Laminated calcium sulphate alternating with very thin carbonate interlaminae and having two different aspects; one being even and continuous and the other of a wavy, irregular appearance (subtidal, intertidal, and supratidal deposits). Nodular calcium sulphate beds, usually associated with wavy, irregular laminated beds (supratidal, sabkha deposits); very coarsely crystalline gypsum beds (selenite), associated with more even, laminated beds (subaqueous, intertidal to subtidal deposits); wavy anastomozing gypsum beds, composed of very fine, often broken crystals (subaqueous, current-swept deposits); halite having hopper and chevron structures (supratidal to intertidal); and halite, potash salts, etc. having continuous laminated structure (subaqueous, possibly basinal). Evidence for diagenetic changes is observed in the calcium sulphate deposits which apparently formed by tectonic stress and also by migrating hypersaline waters. These observations suggest that the common, massive form of alabastrine gypsum (or anhydrite, in the subsurface) may not always be ascribed to original depositional features, to syndiagenesis or to early diagenesis but may be the result of late diagenesis. 相似文献
17.
辽宁省兴城市夹山地区中元古界长城系白云岩中首次发现叠层石,其产出层位为前人在这一地区划分的"常州沟组"顶部,自下而上为Stratifera sp.层叠层石(未定种),Cryptozoon sp.卷心菜叠层石(未定种),Eucapsiphora sp.叠球藻叠层石(未定种)。该组合以及邻区葫芦岛等地团山子组中的叠层石类型均属于燕山、太行地区团山子组叠层石组合带分子。上述叠层石的发现为夹山地区划分出团山子组提供了重要的生物地层学证据。根据岩石组合特征、叠层石形态垂向分布规律及其与古环境演化的关系分析,认为兴城地区团山子组沉积环境演化为海退沉积序列(浅滩到潮间、潮上带)到海侵沉积序列(潮间、潮上带到潮间、潮下带)。 相似文献
18.
P. S. Plummer 《Australian Journal of Earth Sciences》2013,60(7-8):395-402
Four distinct sedimentary facies have been recognized within the upper Precambrian Nuccaleena Formation in the central Flinders Ranges of South Australia. Three dolomite facies, containing tepee structures within either well‐laminated or stromatolitic dolomite, were deposited within supratidal and intertidal environments, whilst an interbedded shale and dolomite facies originated under very shallow submerged conditions. 相似文献
19.
As a contribution to a project on the role of aerobic heterotrophic bacteria in the organic matter turnover within cyanobacterial mats, we investigated selected lipid classes of five morphologically different microbial mats from the intertidal area of Abu Dhabi, United Arab Emirates. The mats thrive under extreme environmental conditions as they are exposed to salinity up to 200 and shadowless sunshine for nearly 12 h per day. The total extractable organic matter is characterised by heavy δ13C values of −17‰ to −10‰, suggesting CO2 limitation. The lipids reflect the biomass of the principal mat-building phototrophic and heterotrophic microorganisms. Moderate amounts of hydrocarbons, mainly cyanobacterial n-heptadecane, short chain monomethyl alkanes and diploptene were detected in all the mats. The ubiquitous n-hexadecanoic acid is dominant amongst the free and ester-bound phospholipid fatty acids (PLFAs), whereas the overall acid composition varies due to differences in the extreme environmental conditions. Additionally, the top layers of two of the five mats were analysed separately to compare their lipid compositions with those of the whole mats. As would be expected, the concentrations of cyanobacterial biomarkers exceed those found in the total mats. Noteworthy is the presence of n-heneicosadiene as predominant hydrocarbon in the top layer of the so called gelatinous mat, which thrives under the locally most extreme conditions. As the n-alkadiene was present to a much lesser extent in the intact mat, it may provide a new biomarker for a so far unknown important aerobic organism. 相似文献
20.
安顺组是位于大冶组和关岭组之间的一套白云岩组合,本文将其分为三个岩性状,重点介绍了沉积成岩白云岩的特征,根据岩石学和沉积学的相关原理分析了安顺组的沉积环境及其演变,明确提出该组为局限碳酸盐台地沉积,至下而上经历第一段的台地边缘浅滩,到第二段的潮间至潮上带,再到第三段的潮上带的演变过程,从而形成黔中碳酸盐台地及其前缘缓坡... 相似文献